TFT Liquid Crystal Displays are widely applied to different products such as handset apparatus, notebooks, monitors and flat TVs on the strength of their characteristics including thinner, lighter in weight, and lower power consumption in comparison with traditional CRTs (Cathode Ray Tubes).
A TFT Liquid Crystal Display comprises a backlight module and an LCD module. The light emitted from the backlight module passes through the LCD module and is converted into a plurality of different color lights for image display. The LCD module includes a first polarizer, a first glass substrate, a color filter, a liquid crystal layer, a second glass substrate, and a second polarizer, wherein the first polarizer and the second polarizer are perpendicular to each other. First, the light emitted from the backlight module is polarized by the first polarizer and gets into the liquid crystal layer. Then, the light is twisted by the liquid crystal layer according to the strength of the electrical field between the two glass substrates for controlling the amount of light passing through the LCD module. Finally, the light is filtered by the color filter composed of a plurality of red, green, and blue sub-pixel color filters for generating the different color lights.
The backlight module includes a light-emitting element, a plurality of optical films, and optionally a light guide plate. The light-emitting element is typically a cold cathode fluorescent lamp (“CCFL”) device, a combination of a blue light-emitting diode (“LED”) and a fluorescent material like YAG, or a combination of a red, a blue, and a green LEDs for providing white light to travel through the LCD module. The optical films include several prism sheets and a diffuser for increasing the light efficiency and uniformity; the light guide plate is a transparent body for guiding the light emitted from light-emitting element to a desired direction. As to those typical light-emitting elements, there are several disadvantages such as low color saturation and low light efficiency depending on the different light sources and the combinations.